Red Worms VS Black Soldier Fly Larvae - Which is Better for Composting?
Everybody knows about composting. It’s the best way to make something out of your household waste and keep it out of the landfill. But not everybody knows about composting’s bigger, better older brother: vermicomposting (composting with worms). Vermicomposting works basically like composting, but faster, more efficiently, and with even more useful byproducts.
In this article, we’ll talk about the two best bugs you can vermicompost with, how to set up a vermicompost bin, and figure out which worm is right for you. Let’s get into it!
What is Worm Composting?
The crucial concept behind composting is that food scraps, lawn clippings, dead leaves, and even biological waste like manure are full of nutrients. But those nutrients need to be unlocked by some kind of decomposer. Once they break your waste products down, plants in your garden can turn them into vegetables.
Normal composting makes use of microscopic decomposers (bacteria and fungi) to slowly churn up your waste. But this takes time and lots of attention. Compost needs to be aerated and stirred so that the microbes have just enough oxygen, heat, etc. Normal composting can take months to break down one bin worth of compost.
But what if you were to use a macroscopic decomposer, like an earthworm or a fly larva (or a maggot, if you’re not squeamish)? These invertebrates are much more efficient at decomposing on a large scale.
And beyond that, they can produce liquid fertilizer that you can use on your plants right away. Some of them can even produce animal feed for your pets or chickens.
Basically, there are two inverts that people use for vermicomposting. The first is your common earthworm, or red worm. The second is the black soldier fly larva, or BSFL. This thing isn’t a worm, it’s a fly larvae that has some special abilities beyond just eating junk.
Let’s compare the species and how they vary as decomposers.
How Red Worm Composting Works
There are two main red worms that people use for vermicomposting: the red wiggler (Eisenia fetida) and European nightcrawler (Dendrobaena hortensis). Both are strong decomposers and can be used as fishing bait, although nightcrawlers are larger and more appropriate for large-scale outdoor composting.
Red worm composting on a household scale normally involves a compost bin with several drawers. These drawers are full of holes, allowing the worms to move between them. You’ll add fresh waste to the upper drawers, which the worms will break down. As it decomposes, it will fall into the lower drawers, where you will collect it.
You can outfit these bins with a spigot, which will let you collect the “black gold” liquid fertilizer that accumulates at the bottom.
Another red worm composting method involves creating an in-ground bin, with holes that lead out of the composter into your garden. In this method, the worms stick around because of the abundance of fresh waste in the bin. But they will also venture out into your garden to aerate the soil.
How Black Soldier Fly Larvae Composting Works
Composting with black soldier fly larvae (Hermetia illucens) is slightly more complicated, but has some great benefits. A BSFL compost bin involves a main chamber, where the larvae eat just about anything organic.
Like any compost setup, this process produces a ton of heat. As the larvae eat and grow, they will eventually begin the process of pupating into flies. This will cause them to seek cooler temperatures.
To that end, you will have a ready-made ramp in the compost bin that will allow them to wiggle up and out of the bin, into a bucket. At this point, you can collect the larvae and feed them to your chickens.
What Can They Eat?
This is probably the biggest difference between red worms and BSFL. Red worms are very limited in what they can eat. You can’t give red worms meat, dairy, citrus, spicy food, or manure. Any of these things are toxic for red worms, so they either won’t eat them, or might accidentally ingest them and die.
People often focus on using red worms to compost yard waste, like grass and leaves. Large-scale vermicomposting with a bigger species like nightcrawlers is great for this application.
On the other hand, BSFL can safely turn just about anything into compost and chicken food. Their guts are so efficient and processing ammonia and other toxic chemicals that they can even break down manure. They can eat meat, dairy, citrus, and spicy foods, too.
Ideal Environmental Conditions
Because red worms live underground, the only thing they really care about is the temperature of the soil. Vermicomposting with red worms, your goal is to keep the soil between 55° and 80°F. They can survive freezing temps, but they will stop composting under 55°. If you live in an especially cold (or hot) place, this may be a problem.
BSFL have a wider range of temperatures they can effectively compost in. They will continue composting up to 100°F, but ideally prefer temperatures closer to 85°F. You will also want to keep the humidity around 70% inside the compost bin.
Both red worms and BSFL prefer a neutral pH, between 6 and 7.
Which Worm Should You Choose?
Tying it all together, red worms and BSFL are pretty different and your choice will depend on a lot of things.
For small-scale composting (especially indoors) that makes use of all your kitchen scraps and even manure, BSFL are a clear winner. If you’re experimenting with animal husbandry, BSFL also have a clear edge in that they can produce unlimited free feed for your chickens.
But if you’re interested in a more large-scale operation focusing more on yard waste (grass, leaves, etc.), red worms can be easier to maintain and easier to scale up. Red worms can also be set up to spread into your garden, automatically spreading plant nutrients and aerating the soil.
Ultimately, it depends on what kind of homestead you have, and what you want your compost bin to do for you.